Abstract:

The Deinococcus radiodurans, Saccharomyces cerevisiae and Escherichia coli were selected as organic substrate for simulatingbiomineralizationofcarbonatetostudythemodulationeffectsforcalciumandstrontiumbiomineralization.Thecrystal morphology,phaseandgrainsizewereanalyzedwithSEM,FT-IRandXRD.Theresultsshowedthat:(1)when[Ca2+]/[Sr2+]=2,amixture ofaragoniteandcolumnarcalcitecrystalswasformedwithouttheadditionofmicrobe,butthespindle-shapedcalcitecrystalwasformed inthemicrobialgroup.Atpresent,3kindsofmicrobeswereabletoinducestrontiumionsintothecalciumcarbonatecrystal;(2)when [Ca2+]/[Sr2+]=1,thesparsespindle-shapedaragonitecrystalswereformedintheabsenceofbacteria.Theclosespindle-shapedand aragoniteclustercrystalswereformedintheadditionof Saccharomyces cerevisiae or Escherichia coli.Theycanpartlyinhibitthe strontiumionsintothecalciumcarbonatecrystal.Whilethecrystalswerecauliflower-likecalciteinDeinococcus radioduransgroup,it stillcaninducethestrontiumionstodisplacecalciumions;(3)when[Ca2+]/[Sr2+]=0.5,aragoniteaggregatewithirregularsizewas formedintheabsenceofbacteria.Thespindle-shapedoraragoniteclustercrystalswereformedinthemicrobialsystem,theycanpartly

inhibitthestrontiumionsintothecalciumcarbonatecrystal.Theresultssuggestedthatthehighconcentrationofcalciumionsmaybe favorabletocalcitephase,whilehighconcentrationofstrontiumionstoaragonitephase.

Key words: biomineralization;microorganism;calciumion;strontiumion